gpiolib: of: add a quirk for legacy names in Mediatek mt2701-cs42448
The driver is using non-standard "i2s1-in-sel-gpio1" and
"i2s1-in-sel-gpio2" names to describe its gpios. In preparation to
converting to the standard naming (i2s1-in-sel-gpios) and switching the
driver to gpiod API add a quirk to gpiolib to keep compatibility with
existing DTSes.